Syllogism is an important topic in the Reasoning section of various competitive exams like IBPS PO, IBPS Clerk, SBI PO, SBI Clerk, IBPS RRB, SSC CGL, SSC CHSL, Railways Group D, NTPC, and many others. Syllogism is a fundamental concept in logical reasoning and involves drawing conclusions based on two or more premises. To master syllogisms, practice is key. Practicing with a variety of syllogism questions with answers, both simple and complex, can improve your logical reasoning skills and help you perform well in exams. Smartkeeda provides you with unlimited free syllogism questions pdf and syllogism reasoning questions with answers pdf that you can download and practice for free and improve your skills for your upcoming exams.
Syllogism is a way of arguing that uses two statements to prove a third statement is true. For example, consider the argument: "All humans are mortal; I am a human, therefore I am mortal." This is a syllogism. Syllogism reasoning questions test a candidate's fundamental aptitude and ability to draw conclusions from given statements using a step-by-step approach to problem-solving. When solving syllogism questions in reasoning, it's essential to assume that the given statements are absolutely true, even if they may seem illogical at times.
The general structure of syllogism typically consists of three parts:
Conclusion: The third statement, derived from the major and minor premises. In our example, it's "No engineer is a nurse.
There are four basic types of categorical statements that form the foundation of syllogism premises and conclusions accurately. These categorical statements are essential for understanding and analyzing syllogistic reasoning:
This statement asserts that every element in category A is also in category B.
This statement declares that there is no overlap between categories A and B; none of the elements in A belong to B.
This statement acknowledges that there is at least one element in category A that is also in category B. It doesn't specify how many.
This statement implies that there is at least one element in category A that does not belong to category B.
By carefully analyzing these statements and their combinations, you can effectively solve syllogism questions and assess the validity of conclusions in logical reasoning problems.
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Conclusions in Syllogism
There are three types of conclusions in Syllogism:
It depends on the combination of statements, and what the conclusion would be. Here are some handy rules to quickly solve syllogism questions and move to conclusions:
1. All + All = All:
If you have statements like "All A are B" and "All B are C," you can conclude that "All A are C."
2. All + No = No:
If you have statements like "All A are B" and "No B are C," then you can conclude that "No A are C."
3. All + Some = No Conclusion:
When you have statements like "All A are B" and "Some B are C," you cannot definitively conclude any relationship between A and C.
4. Some + All = Some:
If you have statements like "Some A are B" and "All B are C," then you can conclude that "Some A are C."
5. Some + No = Some Not:
When you have statements like "Some A are B" and "No B are C," you can conclude that "Some A are not C."
6. Some + Some = No Conclusion:
If you have statements like "Some A are B" and "Some B are C," you cannot definitively conclude any relationship between A and C.
When dealing with syllogism questions, one effective approach is to use Venn diagrams to visualize and analyze the given conditions and conclusions. Using Venn diagrams in syllogism problems can provide a visual and systematic way to analyze the relationships between categories and determine the accuracy of conclusions. It's a valuable tool to ensure that you consider all possible scenarios and arrive at the correct answers in competitive exams and other reasoning assessments.
Here's how it works:
Identify the Categories: Start by identifying the categories or classes mentioned in the premises. For example, if you have statements like "All A are B" and "Some B are C," you have three categories: A, B, and C.
Create Venn Diagrams: Draw circles or ovals to represent each category and overlap them as needed. Use the information from the premises to fill in the diagram. For example, if all A are B, you would place A completely within the circle representing B.
Analyze the Conclusions: After constructing the Venn diagram, you can use it to evaluate the given conclusions. If a conclusion matches the diagram, it is true. If it doesn't match, it's false.
Consider All Cases: It's essential to consider all possible cases. In categorical syllogisms, there are typically four ways two categories can relate: all, some, no, or some not. So, evaluate the conclusions under each of these possibilities.
Apply Logical Rules: In addition to the Venn diagram method, you can apply logical rules such as the "All S are P" rule, which implies that "Some S are P." Understanding these rules can help you quickly assess the validity of conclusions.
1. Statements:
Some bowls are plates.
No plate is a glass.
Conclusions:
I. Some glasses are not bowl.
II. All glasses being bowl is a possibility.
Venn Diagram Method:
Analytical Method:
Some bowls are plates (I) + No plate is a glass (E) = I + E = O = Some bowls are not glasses.
Hence, conclusion I does not follow. But the possibility in II exists. Thus, conclusion II follows.
2. Statements:
All engineers are villagers.
No villager is a nurse.
All nurses are managers.
Conclusions:
No engineer is a manager.
All villagers being managers is a possibility
Venn Diagram Method:
Analytical Method:
No villager is a nurse (E) + All nurses are managers (A) = E + A = O = Some managers are not villagers (O). Thus, the possibility in II exists.
Again, All engineers are villagers (A) + No villager is a nurse (E) = A + E = E = No engineer is a nurse (E) +
All nurses are managers (A) = E + A = O Some managers are not engineers.
Hence, conclusion I does not follow.
When dealing with syllogisms, some common mistakes to avoid include: